Electric discharge tube



May 15, 1950 J. L. H.,JoNKER p -rAL 2,598,266

ELECTRIC DISQHARGE TUBE Original Filed March 11, 1946 Patented May 16, 1950 UNITED STATES PA'FEN'I?-` OFFICE `ELECTRIC DISCHARGE TUBE Jehan LmleniilgHendrik Jonker and Bernardus Octavianus Maria Gall, Eindhoven, Nethelfe f "lands, assigno'rs'to' Hartiord'National'Bank,and

Trust Company, Hartford, Conn., as trustee" VfOriginal application March 11, 1946, Serial No. 653,502e Divided and this application,V Mateh- 11, 1948, Serial No. 14,214. In the Netherlands;

N ovembe 14, 1942 Section 1, PublicLaw 690Augf-ust 8, 1946 Patent expires November 14, 1962 5 Claims. (Cl. Z50-@2:75)

(This invention relates to an electric discharge tube and particularly to the construction of theV elctrde system comprising a cathode'and one or more electrodes acting'asA grids and/or as the anode. This application is a division of my copending application Serial No. 653,502 led March 1'1, 1946.

o The electrode system of the tube according to the invention has been obtained by starting with two or more concentric conductors separated from each other by insulating material, by decreasing vthe dimensions of this structure by drawing, hammering or similar operations and finally by removing one or moreof the conductors and the intermediate insulating material for part of the circumference, Thus, ank inner conductor is ultimately caused to lie o pen and this conductor constitutes the cathode, of the electrode system concerned, the othe'electrodes of the system being formedlbyl the edges of the Paltly remove@ @91?111913015 CQHQSHTQE'Y al raggd'arund. this inner conductor: For the purpose here described the inner conductory mayA be coated with*emittingrnateriaifor at least part of its length; it is, however, also possible to constitute y the pulverulentinsulating material contained between this inner conductorrv arnitbe next fol-il lowingconductor by readily?"enflitting4 material, :for` `eiiarnple barium4 oxide, the outer conductors being removed as far as the-bariumoxide layer just mentioned, after. the` structu''ren of conductors separatedfrom each other byinsuiating mate-` rial is drawn out.

I The system thus obtained has veryV important of uniting any number of electrodes, 'such as aY cathode, several gridsv and an anode to form a rigid aggregate, the various electrodes being arrangedso as to be very closely spaced. This is, for example, important in connection with dise` charge tubes for short and ultra-short wave purposes. In this case ther beam of electrons emerging fromthe cathode passes the edges of the var-V ious concentric conductors and may impinge for egainple on an individual anode arranged to surrdund the latter.

, Y A further very important advantage of the invention resides in that the system may be formed in any shape, so that thedistance between the various electrodes cannot be. altered; particularly istobe borne in mind the useof this systemin gasfilled tubes for examplef'for advertisement pnrposes in which the cathode .is arranged vopposite `a fluorescent electrode and a structure according to the invention, which in this case acts as, a cathode. and.' a fasille elcfwda. gante, Shaped in `am' formV Whatever Such as, 1ettera-,-

gives; Figures, itali@ wereaehreinbfore misuse @reiche ac eraf ing to the i ventioncontaining anelectrode s sting'or receiving valve r as altube for advertise ment purposes was ref, red to, another possibility,

Gif appuie-11011 iS tg flildfwte Einem tubes; having, a line-shapdfus it, heine psjsible tal use the structureoftwo ormore concentric conf successively to4 forma' cathode. a lWehnelt cylinderna suppressorvanod'e and so forth.

The materials frein Whiclithe layers built upto form suoh an electrode sy'sftervn. are mademayfbe formedby various metals and' insulating mata.

rials; generally speaking; itis advantageous'tdf choose as such respectively the metals that? are usuallyA employed @Si eltifl).d` material' Such 345,2 nickel, tungsten, molybdenunior the like and irlorganic insulating substances as intermediate, layers such as magnesia, alumina, beryllia,l zirconium oxide or the like., use being made in the above mentioned. case, fr at, least one. layer, f.

barium .oxide which, 1,166` constitutes the emitting,

substance.

The. layers may be removed iriva'rQuS-ways; preferably, hQWGVr, this iseiected' by. s .ec'lfianica l `r means, for example. by, grinding' since` thisrer- 'mits Ofthe Correct dimensiansfbeine adhered t9' for the System *G0-be ma e These dIrienSQns; ssble t0 obtain enf now, bev described; mre u11y` with reirenqe, tg

the accompanrinadrewna"inwhich twi fo,

of constructed .ofthe lec,fmldfi System. of a dil'if charge tube'according to the invention are sl'iovvn4 and with reference. .t9 pcsihlity of Acanstrllftlfl' fol: the' manufactured" Sach a System, listed.'-V

ring to FigureV 1, designates' animer, CQndiltQr surrounded by condutglis and Thespace between the ,various onglueters,` sprovded hl insulating materiel, for example 6 mames@ ,6152 1 alumina The variole @Qndnctors are arranged" concentrically and areA remo d' for part Qfj.P he j' circumterence ,so'thatthe maar cpnductpr l caused to lie open; At that open part this cg ductor is coated with emitting material 5 andacts as the cathode. In this case, the conductors 2 and alsolid aggregate and;

3 form, at the edges 6, the grids of this system. The electrode systemis enclosed in an envelope 20. In the system shown in FigureY 2 an inner conductor 'l is surrounded by three conductors 8, 9, I0. The intermediate spaces Il between the conductors 8 and 9 and between!) and lil are provided with insulating material, for examplel magnesia or alumina, a readily emitting substance, for example barium oxide, beingrprovided between l and 8, and hence in the space l2, and acting as the cathode on that 'side (i3) where apazce v l -annulus, and solid insulating material interposed the outer conductors and the intermediate in-.

sulating material are removed. The electrode system is enclosed in an envelope 2l. In this case, the edges I4 of the various tubular conductors arranged to surround the inner conductor form the auxiliary electrodes which may inuence the beam issuing from the cathode.

The structure of electrodes of the kind here described may be made in the following manner: internally of a tubemade for example of nickel and whose length is 1 m., its diameter being 12 mm. and its wall thickness 1 mm., is arranged another equally long tube which has a diameter of 6 mm. and a wall thickness oi 0.5 mm. and which has arranged inside it a wire which is also made of nickel and whose thickness is 2 mm. The intermediate spaces between the various conductors are provided with magnesia, this operation being preferably effected in vacuo and the said filling being rigidly compressed or shuied. This aggregate is then hammered until an appreciable increase in length is .obtained and then drawn until the desired dimensions are reached. These dimensions may be for example a length of 100 m., an external diameter of 1.0 mm., a wire thickness of the inner conductor of 0.2 mm., a wall thickness of the outer conductor of 0.1 mm. and a distance between the various conductors of 0.125 mm. The outer conductors and the intermediate insulating material are then removed for part of the circumference, it being possible to effect this operation for example by grinding. The part of the inner conductor which is thus caused to lie open is coated with emitting material and the aggregate thus obtained is to be used as an electrode system. In this case, a wire coated with emitting Vmaterial constitutes a directly heated cathode. As an alternative, however, the outer conductors may be removed as far as the innerconductor but one and then the rst conductr that is concentric with the inner conductor may therefore be coated with emitting material. Thus, an indirectly heated cathode is formed. Finally, in order to avoid interference lfrom the magnetic field, the combination of the two 'innenconductors may be used as a heating element, the current being supplied through one of the conductors and being discharged through the other. In this case the next following conductor towards the'outside forms the cathode body.

For the purpose of strengthening the ground conducto-rs the latter may, if desired, not be removed throughout the entire length so that small bridges of the outer conductor are left, as is schematically denoted in the figure by I5. It isralso important that the filling of the intermediate Aspaces should be constituted byk an insulating powder capable ofA being sintered, for example a mixture of silica, alumina and magnesia.

between and separating said conductors. i, 2. An electric discharge device comprising an envelope, an electrode structure contained with- .in said envelope and comprising a central conductor, a second conductor positioned concentrically with said central conductor and having a cross-section in the shape of a segment of a :first outer annulus with a gap between the annulus ends, and solid insulating material interposed between and separating said conductors and having a cross-section in the shape of a segment of a second inner annulus with a gap between the annulus ends, said inner and outer annuli segmentsbeing positioned with parts of said gaps in radial alignment.

3. An electric discharge device comprising an envelope, and an electrode structure within said envelope and comprising a central inner con-v ductor, a second outer conductor positioned concentrically with said central conductor, said second conductor having a cross-section in the shape of 'a segment of a rst outer annulus and an insulating material interposed between and separating said conductors, said insulating material having a cross-section in the shape of a segment of a second inner annulus, and an electron emissive coating on an outer surface portion of said inner conductor, said inner and outer annuli segments having gaps between the ends of said annulus segments and being positioned with parts of said gaps in radial alignment with said electron emissive coating.

4. An electric discharge device comprising an envelope and an electrode structure contained Within said envelope and comprisingva central conductor, a second outer conductor positioned concentrically with said central conductor and 'with said central conductor and having a crosssection in the shape of a segment of an annulus, and insulating material interposed between and separating said conductors, and comprising a sintered mixture of silica, alumina, and magnesia.

JOHAN LODEWIJK HENDRIK JONKER. BERNARDUS OCTAVIANU S MARIA GALL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,859,522 Miessner May 24, 1932 1,961,192 Bowles June 5, 1934 2,107,945 Hull et al. Feb. 8, 1938 2,312,723

Llewellyn Mar. 2, 1943 

